using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Demo
{
    class SumUtils
    {
        public int Add(int num1, int num2)
        {
            return num1 + num2;
        }
        public double Add(double num1, double num2)
        {
            return num1 + num2;
        }
        public string Add(string str1, string str2)
        {
            return str1 + str2;
        }
        public int Add(int num)
        {
            int sum = 0;
            for (int i = 0; i <= num; i++)
            {
                sum += i;
            }
            return sum;
        }

        public SumUtils()
        {

        }
    }
}
